Carphonewarehouse

Has the Carphone Warehouse Custom Service been lie to me?

I was aware from credit experience system I owed the Carphone Warehouse debts a few months ago. I provided all my previous letters to the Carphone to show that I have written to cancel my contract when my previous contract expired. However….
In order to clear my credit record, I paid the requested amount of money, although I did not think that was fair. I asked them to send bill to me as I want to understand where those bills were from. Unfortunately, I still have not got it after 2 months waiting.
I wrote emails to ask them. The response was always that they posted the bill to me, if I have not got it, they would re-sent it to me again and asked me to wait for another 3-5working days. I have never experienced of losing mail previously. I wonder if people who work for the Carphone Warehouse custom office have been lying to me.